Carburetor deicing system



Oct.- 25, 1960 Filed June 21, 1957 F- W. COOK ETAL CARBURETOR DEICINGSYSTEM 3 Sheets-Sheet 1 I N VEN TOR.

FORREST W.COOK JAMES E. EBERHARDT @WMW' AT TOR NEY Oct. 25, 1960 F. w.COOK ETAL 2,957,685

i CARBURETOR DEICING SYSTEM Filed June 21 1957 3 Sheets-Sheet 2INVENTOR.

FORREST W. COOK JAMES E. EBERHARDT ORNEY Oct. 25, 1960 F. w. cooK ETALCARBURETOR DEICING SYSTEM Filed June 21, 1957 3 Sheets-Sheet 3 54 as T1.289 86 82 86 7798 77 I 77 '& %''I )Q Q 7.; I ///////1\ 76 e7 INVENTOR.

FIG 8 FORRESTWCOOK BY JAMES E. EBERHARDT fiMm/m ATTORNEY United StatesPatent 2,957,685 CARBURETOR DEICING SYSTEM Forrest W. 'Cook, and JamesE. Eberhardt, Trenton, Mich., assignors to ACE Industries, Incorporated,New York, N.Y'., a corporation of New alersey Filed June 21, 19-57, Ser.No. 667,111

1 Claim. (Cl. 261-129)v This invention relates to carburetors forinternal combustion engines and, more particularly, to means forreducing or preventing the formation of ice on and around the throttlevalve.

During cool, humid weather, the evaporation of gaso line duringcarburetion causes ice to form on the throttle valve, the mixingconduit, and the idle ports. When the throttle valve is moved to nearidleposition, the ice formation bridges the space between the throttlevalve and the wall of the mixing conduit, and causes stalling of theengine.

As the formation of'ice in the carburetor usually occurs when thethrottle valve is in idle or near idle positions, due to the rapidexpansion of the fuel-air mixture posterior to the throttle valve, it isan object of the invention todirect heated air into the mixing conduitadja cent the throttle valve when the latter is in idle or near idlepositions to thereby reduce icing and prevent stalling of the engine.

Another object of the invention is to provide means for forming anddischarging a heated fuel-air mixture toward the posterior side of athrottle valve when the latter is in slightly open position.

A further object of the invention is to draw heated air from a suctionresponsive device in an automatic choke control housing into an idlingfuel passage to heat the fuel passing therethrough during idling of theengine.

The invention embodies other novel features, details of construction,and arrangement of parts, which are hereinafter set forth in thespecification and claim, and illustrated in the accompanying drawings,wherein:

Fig. 1 is an elevation view, partly in section,.illustratin a stove, anda carburetor embodying features of the invention.

Fig. 2 is a fragmentary schematic sectional elevation view taken in thedirection of the arrow in Fig. 1.

V Fig. 3 is a fragmentary sectional view takenalongthe line 3-3 ofFig.2. V

Fig. 4 is a fragmentary sectional view taken along the line 44 of Fig.3.

Fig. 5 is a schematic view illustrating a modified form of theinvention.

Fig. 6 is a fragmentary vertical sectional view.

Fig. 7 is a fragmentary bottom view.

Fig. 8 is a fragmentary sectional view taken along the line 8-8 of Fig.7.

Referring now to the drawings for a better understanding of theinvention and, more particularly, to Figs. 1 to 4 therein, a downdraftcarburetor is shown as comprising an air horn section 6, a main bodysection 7, and an outlet section 8 having a flange 9 for attachment toan intake manifold 11. The air horn section has an air inlet passage 12communicating with a mixing passage 13 provided in the body section 7and outlet section 8.

A constant level float bowl 14 on the body section 7 is provided withthe usual inlet needle valve 16 controlled by a float 17. A fuelmetering orifice 18 controlled by a 2,957,685 Patented Oct. 25, 1960metering rod 19 leads from the float bowl to main fuel passage 21 havinga nozzle 22 disposed to discharge fuel into a primary venturi tube 23.

An idling fuel system is shown as comprising a passage 24 leadingupwardly from the main fuel passage 21 and having an idle orifice tube26 communicating with a passage 27 leading to a vertically elongatedidle port 28 and an adjustable idle port 29 having an idling adjustmentscrew 31. A metering restriction 32 is provided in the passage 27, andan air by-pass 33 leads to the passage intermediate the orifice tube 26and said restriction.

A choke valve 34 is fixed on a shaft 36 journaled in the horn section 6,one end of said shaft projecting into a choke control housing 37 havinga partition 38 and cover 39 secured thereon by means of screws 41. Abifurcated stud 42 is fixed on the cover to receive and engage the innerend of a spirally wound bimetallic thermostat 43, the outer end of thethermostat engaging the end of a crank '44, which is fixed on the shaft36 and projects through an arcuate slot '46 in the partition 38.

A cylinder 47 is provided in the housing 37 to receive a piston 48connected to the crank 44 by a link 49. A suction passage 51 leads fromthe cylinder 47, below the piston 48, to a suction port 52 in the wallof the mixing conduit 13 posterior to the edge of a throttle valve 53when the latter is in its idle position. A stove 54, having an air inlet56- and air outlet 57, is mounted on an exhaust manifold 58 to supplyheated air through a conduit 59 to a control housing inlet 61 and thenceinto the chamber between the partition 38 and cover 39. A bypass groove62 is formed in the wall of the cylinder 47 for the passage of heatedair from the housing 37 to the passage 51 when the top of thepiston 48is in the cylinder 47 far enough to uncover the top of groove 62. Anidle bleed branch passage 45, having a restricted orifice 50, leads fromthe suction passage 51 to the idle passage 27.

The throttle valve 53 is fixed on a shaft 63 journaled at its ends inthe outlet section 8, and is connected through a suitable link and leverarrangement to a manually operable accelerator pedal.

In the operation of an internal combustion engine provided with acarburetor of the type thus shown and described, the thermostat 43 actsthrough the crank 44 to yieldably resist opening movement of the chokevalve 34 when the engine is cold, and permits free opening moven'ientofthe choke valve when the engine attains its proper operating"temperature.

Upon starting of a cold engine, engine suction is applied through thesuction port 52 and the idle ports 28 and 29 to create a suction inpassage Sland cylinder 47, drawing the piston 48 into the cylinder untilthe top of the piston has uncovered the top of groove 62, thus effectingthe initial opening or pull-01f of choke valve 34. As the engine warmsup, heated air from stove 54 is drawn across the thermostat '43 causingit to expand, the piston 48 is constantly urged downwardly by suction,and the choke valve gradually moves to its full open position.

When the throttle valve 53 is in idle position, as shown in Figs. 1 and4, intake manifold suction draws heated air from the stove 54 into thechoke housing 37 and through the bypass groove 62 into the suctionpassage 51. Some of the heated air is discharged through the port 52into the mixing conduit 13 posterior to the throttle valve, and theremainder of the heated air passes from the suction conduit 51 throughthe idle bleed branch passage 45 and restricted orifice 50 into the idlepassage 27 to mix with and heat the idle fuel passing therethrough fordischarge through the idle ports 28 and 29. By employing the heated airpassing from the choke housing to heat the idle fuel and throttle valve,icing of said valve and the mixing conduit is materially reduced orprevented.

Figs. 5 through 8 illustrate two primary mixing conduits of a two-stage,four barrel carburetor embodying a modified form of the invention. Thecarburetor is shown as comprising an air horn section 66 and a bodysection 67, the latter having two primary mixing conduits 68 providedwith venturi tubes 69 to receive fuel from main fuel nozzles 71. A chokevalve 72, provided in the air horn section 66, is operatively connectedto an automatic choke control mechanism 73 by a suitable conventionallinkage (not shown). Primary throttle valves 74 are disposed in theirrespective mixing conduits 68 and fixed on a common shaft 75 adapted tobe manually operated from an accelerator pedal.

Each primary mixing conduit 68 is provided with an idling fuel systemcomprising an idle passage 76 leading from a fuel bowl to idle ports 77and 78, the port 78 being provided with an adjustment screw 79. Thebody. section 67 is adapted to be secured to an intake manifold 11 toform a plurality of hot air chambers 81, 82 and 83 interconnected bypassages 84 and 85, for warming the walls of the mixing conduits 68.Each idle passage '76 is connected to the chamber 82 by a hot air idlebleed passage 86.

An automatic choke control mechanism 73 of the type heretofore describedis shown as comprising a choke housing 87 having an inlet 88 to receiveheated air from a stove on an exhaust manifold. When the throttle valves74 are in idle or near idle positions, all the heated air is drawn fromthe choke housing 87 through a passage 89 and restricted orifice 91 intothe hot air chambers 81, 82 and 83 for discharge through the passages 86into their respective idle passages 76 to mix with and heat the fuelpassing therethrough. By discharging a heated idling fuel mixturethrough the idle ports 77 and 78 into the mixing conduits adjacent thethrottle valves, it has been found that engine failure due to icing isprevented.

An important feature of the present invention is to pro vide acarburetor choke control arrangement in which the drawing of heated airfrom the choke control mechanism into the idle fuel system and themixing conduit to reduce icing does not adversely affect the operationof the piston inopening the choke valve when the throttle is in idlingtion actingon the choke piston, plus the additional quan; tity of heatedair drawn across the choke thermostat, permits the choke valve to openslightly more, providing additional air for fast or off idle operation,as fully described above.

Another important feature of the invention resides in a carburetionsystem adapted to provide a smooth, stable idling operation of an engineby bleeding heated air into theidling fuel system to maintain a moreuniform tem: perature.

While the invention has been shown in but two forms, it is obvious tothose skilled in the art that it is not so limited, but is susceptibleof various changes and modifications without departingfrom the scope ofthe invention as defined in the claim.

We claim:

A charge forming device for an internal combustion v engine comprising abody'portion having a mixture con- 3 connected to said choke valve andtending to close said choke valve with a force that decreases withincrease in engine temperature; a suction device in said body portionresponsive to engine vacuum operatively connected to said choke valvetending to open said choke valve when said engine is running; a remotesource of engine heat; a

heat passage connecting said remote source of engine heat, said housing,and said suction responsive device and discharging into said mixtureconduit at a point posteror said throttle valve; an idle fuel system insaid body portion for-supplying regulated amounts of fuel from said mainposition, due to the increase in suction posterior to the throttleduring idling. When the throttle is moved from idle toward openposition, the idle ports are unrestricted by the throttle totherebyincrease the suction within the suction passage leading to thechoke housing cylinder below the suction piston therein, and increasethe quantity i 2 of heated air drawn into the mixing conduit through theidle ports, rather than reducing the quantity of heated air drawn intothe mixing conduit, as occurs with a conventional choke control suctionline discharging posterior to the throttle valve. Therefore, additionalheated air is provided when icing is most likely to occur, that is, atfast or on idle operation, and obviously the increased sucfuel supplytosaid mixture conduit to a vertically elongated port adjacent saidthrottle valve and to an adjustable idle port spaced from said firstport and generally laterally of said heat passage discharge in saidmixture conduit; and a passageway in said body portion connecting saidcontinuous passageway and said idle fuel system for-supplying heated airto said idle fuel system, said lastnamed ,passageway having a restrictedorifice formed therein, whereby additional heated air is provided duringfast idle operation.

- References Cited in the file of this patent UNITED STATES PATENTS2,269,706 Brown Jan. 3, 1942 2,429,781 Udale Oct. 28, 1947 2,684,058Boyce July 20, 1954 Sutton, Oct. 4, 1955

